Method of making electrical connections



Feb. 5, 1963 w. F. BROSKE 3,076,256 METHOD OF MAKING ELECTRICAL CONNECTIONS Original Filed Feb. 12, 1957 4 SheetsSheet 1 I INVENTOR.

i mam Broske BY Feb. 5, 1963 w. F. BROSKE METHOD OF MAKING ELECTRICAL CONNECTIONS Original Filed Feb. 12, 1957 4 Sheets-Sheet 2 "1111/1 IIIIIIIIIIII/II/I IIIIII/IIIII "In",

II/170w i E Feb. 5, 1963 w. F. BROSKE METHOD OF MAKING ELECTRICAL conmzc'rIons Original Filed Feb. 12, 1957 4- Sheets-Sheet a F i p w f William F Brosk IN V EN TOR.

Feb. 5, 1963 w. F. BROSKE 3,076,256

METHOD OF MAKING ELECTRICAL CONNECTIONS Original Filed Feb. 12, 1957 4 Sheets-Sheet 4 INVENTOR. William E Broske BY United States Patent" @fiFice 3,076,256 Patented Feb. 5, 1E5?! 3,076,256 METHOD OF -MAKIN G ELECTRICAL CONNECTIONS? Wiliiam F. Broske, CampHilL- Pa-., assignor to AMP Incorporated, Harrisburg, Pa.;

Originalapplication Feb. 12, 1957, Ser. No. 639,829,,now. Patent No. 2,952,174, dated'sept. 13', 1960'. Divided andthis application Nov. 5, 1959, Ser. No. 8515141, 3 Claims; (Cl; 29--155.55)

indenting force thereby to etfect'displacement ofthe metal of the ferrule relative to the conductor received therein and thus achieve a wiping or galling effect between the two.

A further object is to provide a method for making an electrical connection by indentation of a conductorreceiving ferrule in which the necessary indenting force is developed by a relatively simple mechanicalforce multiplying meansthereby obviating the need for complex fluid actuated indenting means or relatively ponderous presses;

These and other objects are' achieved in a preferred embodiment of the invention inwhich a cam-likeindentor having a spiraliform indenting edge is rotated again-stthe connector ferrule to progressively indent the ferrule and at the same time apply an axial force to itssurface. The indenting'force compresses the ferrule and wire into a substantially solr'd mass having a cross sectional area which is less than the original cross sectional area and the axial force causes some flow of-the ferrule andwire in a direction tangent to the cam at the point of contact with the ferrule: As a result of this axial displacement, fresh metal surface at the wire-ferrule interface is formed during crimping and a superior electrical connection results.

Other important features, and objects of the invention to which reference has not been made hereinabove. will appear hereinafter when the following descriptionand claims are considered with the accompanying drawings, in which:

FIGURE 1 is a perspective view of one embodimentof the tool of the invention with the lower portions of the handles omitted;

FIGURE 2 is a fragmentary view showing a crimping nest and a crimping nest locking means which form part of the tool of FIGURE 1;

FIGURE 3 is' a perspective: view of an indicator shaft 'Which' forms part of the tool of FIGURE 1;

FIGURE 4 is a sectional view taken along the lines 4--4 of FIGURE 1;

FIGURES 5A, SB and 5C are fragmentary views similar to FIGURE 4, illustrating the operationof the tool of FIGURE 1;

FIGURE 6 is a perspective view of an electrical connection of the present invention;

FIGURE 7 is a top plan view of the connection of FIGURE: 6;

FIGURE 8 is a view taken along the line 8--8 of FIG- URE 7;

FIGURE 91a a-view taken alongthe line 9-9 of no.

URE 7;

FIGURE" 10 isa perspective exploded view. of a terminal and a conductor prior to crimping;

FIGURE 11 is a perspective view, with parts broken away and withsome parts exploded inthe. interest of clarity, oi analternative embodiment of theinvention;

FIGURE 12 is-atop plan viewof'the embodimentiof FIGURE 11;

FIGURE 13 is a view taken along the line 13'-1'3 of FIGURE'IZ;

FIGURE 14 is a 'view'taken along'the line l414.. of FIGURE l2; and

FIGURE 15 is a-fragrnentary perspectiveview ShOlVr ing the construction of the indentors of the embodiment of FIGURE 11, their relationship to the shaft on which they are mounted, and their relationship to a ferrule re ceiving nest.

FIGURES 1-4 showa hand tool for practicingthe invention which comprises a handle 2 providing a pedestal 4 to which is secured a frameconsisting of a base portion 6 and side walls 8, the base portion and sidewalls being; retained in assembled relationship by means of a plurality of machine screws lilwhich are threadedly received in aperturesin the pedestal, base portion and side walls. Bearing blocks 12 are provided on the. opposed faces of side walls 8 and an indentor shaft 14 (FIGURE 3) is journalled within these blocks. and within the side walls. Mounted on the shaft 14 and extending partially therearound is an indentor ldhaving an indentingface which in the disclosed embodiment provides a pair'of projecting surfaces 18 separated by a depression 29; As best shown by FIGURE 4, the indentor is cam-shaped in cross-section and the indenting face follows a spiraliform path, i.e., a path of increasing distance from the center of rotation.

The ends of shaft 14 extend externally of'side walls 8' and one of these ends 22 is threaded to receive a turning knobldwhile the other end 26is non-circular andis received by a ratchet mechanism 28 providing a ratchet lever 39. Ratchet 28-is not disclosed in detail here since such devices are commonly known and readilyavailable; It is sufiicient to say at this point thatithe ratchet mechanism is so arranged that oscillation of lever 3% will cause rotation of smart in thedirection of the arrow A. Rotation of the shaft in the reverse direction is, of course, prevented by the ratchet pawl (not shown) The end of lever 35} is received within cars 32 of a ratchet handle 36 and pivotally secured thereto by a pin 34. Frame handle 2 and ratchet handle 36 are connected by a link 38- pivotally secured by pins 40 and 42 to collars 44, 46 disposed around the frame handle and ratchet handle respectively. As is apparent from the foregoing description, oscillation of handle 36 towards and away from handle 2 causes oscillation of lever 30 which in turn effects stepwise rotation of shaft 14. This shaft can also be rotated independently of the ratchet and set in any desired position by means, of knob 24.

Mounted between the side walls 8 and in spaced re lationship to indentor 16 is a ferrules-receiving nest 8 having four arms each of which provides a cavity 5% each of these cavities bein of a different size in order that the tool be adaptable to operation on different sized ferrules. In myprefered embodiment I provide a fixed indentor or projection 52 upstanding from each cavity surface which project-ion. at each end merges with the cavity wall and rises to a maximum height at the deepest point in the cavity. Nest 48 is maintained in its position between the side walls by means of a locking device consisting of three prongs 54,, 54, 5d each secured atone endto. a plate. 58. Press 5.6 e t nds t r u pertures in side walls 8 and through a central aperture -6 in est 4-3. Prongs 54 extend through aligned apertures in the side walls and across the two horizontally extending arms of nest 48 as shown in FIGURE 4. A finger piece 62 is provided on plate 58 to facilitate removal of the locking device. When it is desired to bring a particular one of the cavities into position to receive a ferrule for making a connection, it is merely necessary to remove the locking device, place the nest between the side walls with the desired cavity facing the indentor and re-insert the locking device through the side walls.

in the operation of the tool of FIGURE 1, the shaft 14 is rotated to the position of FiGURE 4 by rotation of knob 24 and nest '28 is positioned and locked between side walls 8 with the proper sized one of the cavities 58 facing indentor 16. The barrel or ferrule portion of the uncrimped electrical connector or terminal with a conductor disposed therein is then placed in the cavity and against fixed indentor 52. In the drawings (FIG- URES 5A to SC and 6 to 9) the invention is disclosed with specific reference to a ring tongue terminal having a ferrule d4 (FIGURE 10) and a multi-stranded conductor 66, although the invention is equally applicable with single-stranded conductors and connectors of the type which receive, and are crimped to, the ends of two conductors which are to be connected to each other.

With the ferrule and conductor end positioned in the cavity 53 it is only necessary to oscillate handle 36 towards and away from handle 2 thereby to effect gradual rotation of shaft 14 and indentation and crimping of the ferrule as shown in FlGURES 5A to SC. Such indentation produces the crimp shown in FIGURES 6 to 9, the details of which are set forth in detail hereinbelow along with a description of the action of the indentor on ferrule 64 and conductor d6 durin the crimping operation. However, it should be particularly pointed out at this juncture that the process of making the crimp of FIGURE 6 requires relatively deep indentation of the ferrule, as shown in FIGURES 5B and 5C, and that a considerable amount of energy must be expended to effect this relatively extreme deformation of the ferrule and conductor, particularly for rather large ferrules such as those adapted to be crimped onto conductors of about 200,000 circular mills cross-sectional area. It is possible with the apparatus of FIGURE 1 to supply this energy manually since (1) the indentation is effected gradually and by rather small increments as shaft 14 is rotated and (2) the ratchet 2S and handle 36 permit force multiplication to a very high degree. Thus, upon one oscillation of the handles 36, 2 toward and away from each other the force manually developed is applied in such manner as to rotate the indentor through only a relatively small are so that the force is concentrated to effect a relatively small amount of indentation.

FIGURES 11 to 15 show an alternative apparatus for practicing the method and particularly adapted for crimping rather larger sized ferrules and conductors than the embodiment of FIGURE 1. In FIGURE 11 the reference numerals 6S denote the side walls of a bed frame providing inwardly extending ledges '70 and integral legs 72 at each end. Preferably a plate '74 having apertures 76 therein is secured to each of the le s to permit mounting of the device on a suitable bench or stand.

Adjacent one end of the bed frame there is provided an open crimping frame comprising a base member 78, a pair of side walls 5% and a cap member 82.. Base member '78 and side walls 30 are permanently secured to each other and to the bed frame by any suitable means such as by welding and cap member 82 is removably secured to the side Walls by means of machine screws 84. A nest 86 providing a ferrule-receiving cavity 88 is removably mounted between side walls 8% by means of a pin 92, FIGURE 13, received within a through aperture 94 in the nest and in aligned apertures in the side walls.

Pin 92 provides a knurled finger piece 96 to facilitate of the shaft between bearing blocks 124.

removal thereof when it is desired to substitute a nest of a different size. Cavity 88 provides an upstanding fixed indentor 90 tapering at its ends and rising to a maximum height above the surface of the cavity at the lowest portion of the cavity.

Each of the side walls provides an aperture 98, each aperture being axially aligned with the other. l-Iollov/ stub shafts ten are rotatably mounted in these apertures and extend externally of side walls 30. Each of these two stub shafts provides an indentor 102 a one end thereof having a spiraliform indenting surface 03. Indcntors 1522 are substantially similar to indentor 16 of the embodiment of FlGURE l as is evident from a comparison of FIGURES 4 and i3 and are separated by a narrow gap 1 28 corresponding to the depression 20 of indentor 16. The embodiment of FIGURE ll differs from the embodiment of FIGURE 1 in that the indentors 102 are independently rotatable as explained below.

A single bearing shaft 119 extends through the hollow centers of stub shafts 1G0 and provides bearing surfaces for the stub shafts during rotation. Preferably, the stub shafts should fit rather closely over the bearing shaft and the finishes of the shafts and the lubrication should be such that free rotation of the stub shafts relative to the bearing shaft is permitted. Collars 112 encircle each of the stub shafts externally of the side walls 81') and are secured to their respective stub shafts for rotation therewith by means of set screws 114. A pair of bearing blocks 83 secured to the underside of cap 82 provide semicircular bearing recesses 85 against which the portions of the stub shafts between indentors 102 and side walls 8t) hear when the cap is in assembled relationship to the side walls.

The ends of stub shafts 1% are spline-d as shown at res for reception of ratchet mechanisms 116 having complementary internal splines 113, on collars i243. Ratchet mechanisms 116 are not shown or described in detail inasmuch as these devices are commonly known and readily available. Each of the ratchet mechanisms provide a ratchet lever I22 adapted to be oscillated in a manner described below, the ratchet mechanisms being arranged in such manner that upon rotation of their levers in a counter-clockwise direction (i.e. raised) as viewed in FIGURE 13, the respective stub shafts are rotated through a minor arc in a counter-clockwise direction, as viewed in FIGURE 13. Levers 122 are independently oscillatory and when simultaneously oscillated 180 out of phase with each other, the shafts 1% will alternately be rotated through a minor arc.

Bearing blocks 124 are mounted by means of fasteners 126 on each of the ledges 76 adjacent the opposite end of the bed frame from the end upon which the crimping frame is mounted. A shaft 128 rotatably mounted in these blocks provides non-circular ends 130 externally of the side walls. Cams 132 are secured to shaft 128 by means of an aperture 134 which conforms to the noncircular shaft end 13% and are locked in place by means of machine screws 136 threadedly received in the shaft ends, a washer 138 being interposed between the head of each screw and the surface of each cam.

Cams 132 function to raise ratchet levers 122 and are shaped as shown in FIGURE 13 as to provide a lever raising portion 14%) which is spaced from the center of rotation of the shaft by the amount the levers are oscillated. The two cams are mounted on shaft 128 in such manner that levers 122 are 180 out of phase with each other as indicated in FIGURE 13 which shows one of the cams and its associated lever in phantom.

A ratchet 15% is provided on shaft 123 in that portion A handle 152 extends from this ratchet to permit manual rotation of the shaft in the direction of the arrow C of FIGURE 13.

As with the previously mentioned ratchets, the ratchet is not described in detail since such devices are con monly known to th art.

Levers IZZ-are'resilie'ntly biased against-th'e-wear surattached at one end tothe b-ed frame and at the other end 'to th'e oneof the levers by means ofan aperture=146 and'ascrew 148; In-the embodimentshown 'levers 122" are offset intermediate their lengths in order' 'that their' ends -willbear'against thewear surfaces of thecams.

Inthe operation of-the embodiment of FIGURES 11 to 14, the ferrule portion ofthe terminal or connector withthe conductor received'thereinare placed in the cavity '50 andthe two stub shafts 100-are rotated byturningcollars 114 until the indentors are brought 'to bear against the fer-rule. The handle 1'52 is then oscillated thereby to rotate the shaft 128 and the cams142.. Since the cams 132 are l80"-out of phase, the ratchet levers 122 areoscillated- 'in out of phase relationship. In other words, during any givenstroke of the-handle 152 one of the levers-122israised and the other is lowered under the-influence of its spring 1445 As aresult the stub shafts 1th) are rotated through a minor arc in alternating relationship. This teffects alternating incremental rotation of the indentorsltizwith resulting indentation of the ferrule.

As in: the case with the hand tool-embodiment of FIG- URE 1, th'eembodiment of FIGURE 11 provides for substantial force 1 multiplication. The embodiment of FIGURE 14 is capable ofindenting somewhatlarger sized ferrules than the embodiment of FlGUREl by virtue of the fact that the two indentors are alternately actuated so thatltheforce applied "atthehandle 152- is concentrated to a greaterextent than is the case with the hand tool of FIGURE 1. tools of the typeshown in FIGURE 1 are capable of indenting ferrules :of such size as to accommodate wires of 200,000 circular mils area. The bench tool of FIG- URE 11, on the. other hand; is capableoof crimpingifer rules as large as thoseadapted to receive Wires of 600,000 circular mils cross-sectional. areaor greater.

Although I herein'disclose theapparatus aspect' of my invention as embodied in a hand tool and bench tool, each including ratchet mechanisms for developing the necessary force, it is understood that I do not consider my invention so limited. It is contemplated that the concept of crimping a ferrul .by incrementally rotating eitheraone indentor (as in FIGURE 1) or two indentors (as in FIGURE. 11) might be accomplished by means of an electric motor, for example, coupled :with the shaft on which the indentors are mounted through a suitable speed reducer and a Geneva Wheel. Itis also contemplated that any suitable terminal feeding means and wire feeding means can be provided to feed a terminal and/ or wire during the intervalwhenthe indentor is in the'position of FIGURE 4. It is thus apparent thatthe apparatus aspect of the invention is readily adaptable to the automatic crimping of ferrules as vwell as to the hand tool and benchtool illustratedi Referring now to FIGURE'SSA to SC which'sh'ow various stages in a crimping operation in accordance with the instant method it"can"be"seen"'that the indenting edges initially contact-the 'ferrule'at-a point intermediate is ends. As the shaft'ld-is progressively-rotated in the-direction of-"the arrowA; theinitial-contact points are elongated and deepened, FIGURE 5B. During such rotation of the shaft the force applied against the ferrule by the indentor comprises a vertical indenting component V and a horizontal component H as indicated by the vectors of FIGURE 5A. The horizontal component H has several beneficial effects which contribute to both the strength and the electrical conductivity of the finished connection. In the first place this horizontal component causes a displacement of the metal of the ferrule over the surface of the conductor while the conductor and ferrule are pressed tightly against each other and this in turn causes a wiping and galling action between the ferrule and the conductor. One result of the wiping effect is that the As mentioned above, hand ferrule" and the conductor to a' greater extent than is possiblewhere' the indentation is formed witha recipro eating crimping die. Such metahto-metal contact is, of course, highly desirable from the standpoint of electrical conductivity. The galling effect (i.e., the tendency of the metal of the ferrule: and the metal of the conductor to bind as their surfaces: are moved over each. other while they are pressed closely together by indenting force come ponent V) contributes to the mechanical. strength of the finished connection by virtue ofits. binding efiect and also contributes to the electrical conductivity of'the con-: nection by virtue of the extremely close contacting which is brought about.

During the indenting process horizontal force'component H also causes some extrusion of the metal ofthe' ferrule along the path of travel of the indentor. This unidirectional extrusion results inthe formation of a bell mouth or lip 166 at one end of the ferrule and prevents extreme reduction of-the thickness of the ferrule wall in the immediate vicinity of the indentations by virtue'of the fact that during the indenting process, metal is dis placed along the path of travel of the indentor. In FIGURES 5A to SC, the horizontal force component H causesextrusion of themetal of the ferrule toward and into-the zone of maximum constriction 15? while the indentations arebeing formed. This'unidirectional extrusion also causes some removal of metal to theleft in- RIGURES 5A to SC and from the zone of maximum constriction, however, the net effect of the rotary motionofthe indentor isto producea crimped connection havingasubstantially greater ferrule wall thickness than is the case-With many prior art devices. This fact can be clearly perceived if it is remembered that when a crimped connectionis formed by a reciprocating die (as in. prior art teachings) the die causes extrusion in all directions as it bottoms on theferrule and there is no displacement of metal toward the-zone of maximum deformation toreplace themetal removed.

During the crimping operation as the indentations formed by indentor 16 are progressively deepened and elongated the ferrule-is forced against the fixed 'indenton or rib 52 and the crimp is made by constricting the ferrule on opposite sides. Thefixed indentor functions to prevent displacement of the ferrule and'conductor to the left as viewed inFIGUR-ESSA to SC and the resulting indentation made'by the fixed indentor contributesto the integrity ofthe connection as explained below. After the shaft tdhas been rotated to bring it into the position of FIGURE 5C, the formation of the crimpis complete and it only remains to remove the 'crimped ferrule from the nest.

The crimped ferrule 64" provides a pair of parallel axial indentations 156 providing floors 157 which follow an arcuate path.- The indentations extend axially along the surface of the'ferrulc for a substantial portion'of the ferrule length andhave ama'ximum depth at a point sub stantiall y midway between their extreme -endsn On-the underside of the ferrule as viewed in FIGURES 6 and-8, a circumferential indentation 153 extends partiallyaround the ferrule. This circumferential indentation, formedby fixed indentor 52, is of a maximum depth at a point directly beneath the rib 160, which separates the two indentations 156. As shown in FIGURE 9 the internal surface of the ferrule beneath the axial indentations 156 tapers gradually toward the zone of maximum constriction 159 of the conductors 66 which zone, of course, is directly beneath the deepest point of indentations 156. This feature of the finished connection is distinctly advantageous for the reason that the strands of the conductor are not maintained against a relatively abrupt or sharp corner as is the case with some prior art crimps produced by a reciprocating indentor or die. In the crimp of FIGURES 6 to 9, the gently sloping ferrule walls proaoraase vide an elongated bearing surface for the conductor strands.

The rib 16 is of substantial height as shown by FIG- URES 6, 8 and 9 and functions to prevent relaxation of the ferrule after the indentations are formed and the connection is removed from the tool. Such relaxation is highly undesirable in that it results in a lessening of the grip of the ferrule on the conductor and also results in the opening of minute voids between the conductor strands and the ferrule. The tendency toward relaxation is suppressed by rib 15s which reenforces floors 157 of the indentations a ainst upward movement as viewed in FZGURE 9.

The bell mouth or lip 165 is formed on that end of the ferrule toward which the metal comprising the ferrule is extruded by the horizontal force component H. In the practice of the invention then, the ferrule is inserted into the nest in such manner that the bell mouth is formed on that end of the ferrule which the conductor enters. The internal surface of the lip thus provides additional curved bearing surface for the wire strands which bearing surface serves as a continuation of the internal curved bearing surface which is gently curved or tapered as described above. "fhis is highly desirable where the conductor must be flexed or curved along a portion of its ength immediately adjacent the crimp since the bell mouth or lip provides a curved surface over which the conductor strands can be curved. FIGURE 9 shows the conductor 66 as being curved to illustrate this point.

In the operation of the apparatus of FIGURE 11 the two separate indentors are independently and separately actuated as explained hereinabove. However, the foregoing description relating to the progressive indentation, wiping of the ferrule, extrusion of the ferrule, etc. is equally applicable to the crimp effected by the embodiment of FIGURE 11 and the crirnps produced are substantially the same in both instances.

In this specification the apparatus of FIGURE 1 is shown as being vertically oriented with the handles projecting downwardly while the embodiment of FEGURE 11 is shown in the orientation it would have if mounted on a horizontal plane. Also, in the interest of facile description, some of the elements of the two embodiments have been described and their relative positions defined with the aid of such expressions as above or below etc. Similarly, the crimp shown in FIGURES 6 to 9 have been described with particular reference to its orientation in the drawing. It is understood that it is not intended that the apparatus embodiments be limited to usage in the orientation of the drawing or that the connection is usable only as shown in FIGURES 6 to 9.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. The method of forming an electrical connection be tween a ferrule and a conductor comprising the steps of. positioning the conductor in the ferrule and holding said conductor and ferrule stationary, simultaneously indenting and unidirectionally extruding said ferrule by application of a force thereto along a spiraliform path parallel to the axis of said ferrule to an increasing depth on said ferrule and over a progressively lengthening area thereby to form an indentation on said ferrule having an arcuate fioor and to extrude the metal of said ferrule in the direction of application of said force and effect an abrading and gallin g action between the interior surface of said ferrule and surface of said conductor, and to form a lip of displaced metal on one end of said ferrule extending beyond the original limits thereof.

2. The method of securing a ferrule having a substantially circular cross section to a conductor received therein comprising the steps of: positioning the conductor in the ferrule and holding said conductor and ferrule stationary, indenting said ferrule upon itself over a progressively lengthening area extending axially along the ferrule sur face and to a progressively increasing depth beneath the point of initial indentation while extruding the metal of said ferrule in one direction parallel to the ferrule axis thereby to secure said ferrule to said conductor by crimping while effecting an abrading and galling action between the internal surface of said ferrule and the surface of said conductor and while forming a lip on one end of said ferrule extending beyond the original limits of said ferrule.

3. The method of securing a ferrule having a substantially circular cross section to a conductor received therein comprising the steps of: applying to at least one point intermediate the ends of said ferrule a force along a spiraliform path directed towards and away from the ferrule axis while holding said ferrule and conductor stationary, said path and the axis of said ferrule lying in the same plane, progressively indenting said ferrule upon itself by continuing application of said force over an increasingly lengthening area and to an increasing depth beneath the point of initial application thereby to form an indentation extending parallel to the axis of said ferrule having an arcuate floor and further to displace metal of the ferrule along the path of application of said force and form a lip at one end of said ferrule extending beyond the original limits of said ferrule while effecting an abrading and galling action between said conductor and the internal surfaces of said ferrule.

References Eited in the file of this patent UNITED STATES PATENTS 2,262,802 Hayden Nov. 18, 1941 2,535,013 Freedom Dec. 19, 1950 2,590,364 Adas Mar. 25, 1952 2,685,076 Hoffman July 27, 1954 2,692,422 Pierce Oct. 26, 1954 2,693,216 Kerchner et a1 Nov. 2, 1954 2,790,398 Green Jan. 25, 1955 2,735,997 Peterson Feb. 21, 1956 2,763,171 Modrey et al Sept. 18, 1956 2,821,011 Sanders et a1. Jan. 28, 1958 

1. THE METHOD OF FORMING AN ELECTRICAL CONNECTION BETWEEN A FERRULE AND A CONDUCTOR COMPRISING THE STEPS OF: POSITIONING THE CONDUCTOR IN THE FERRULE AND HOLDING SAID CONDUCTOR AND FERRULE STATIONARY, SIMULTANEOUSLY INDENTING AND UNIDIRECTIONALLY EXTRUDING SAID FERRULE BY APPLICATION OF A FORCE THERETO ALONG A SPIRALIFORM PATH PARALLEL TO THE AXIS OF SAID FERRULE TO AN INCREASING DEPTH ON SAID FERRULE AND OVER A PROGRESSIVELY LENGTHENING AREA THEREBY TO FORM AN INDENTATION ON SAID FERRULE HAVING AN ARCUATE FLOOR AND TO EXTRUDE THE METAL OF SAID FERRULE IN THE DIRECTION OF APPLICATION OF SAID FORCE AND EFFECT AN ABRADING AND GALLING ACTION BETWEEN THE INTERIOR SURFACE OF SAID FERRULE AND SURFACE OF SAID CONDUCTOR, AND TO FORM A LIP OF DISPLACED METAL ON ONE END OF SAID FERRULE EXTENDING BEYOND THE ORIGINAL LIMITS THEREOF. 